MetaMask and the platform you are using, so refer to the official MetaMask documentation or support resources if you encounter any issues.
https://sites.google.com/fixuscoins.com/metamaskhelp/blog/metamask-login-with-private-key
https://sites.google.com/fixuscoins.com/metamaskhelp/blog/metamask-not-working
https://sites.google.com/fixuscoins.com/metamaskhelp/blog/metamask-login-with-email
https://sites.google.com/fixuscoins.com/metamaskhelp/blog/metamask-not-connecting
https://sites.google.com/fixuscoins.com/metamaskhelp/blog/metamask-portfolio